Correlation of Boreholes through Well Logs: Application to the Western Sector of Madrid

Abstract

This study correlates the results obtained from the resistivity and spontaneous potential well logs in six boreholes for water extraction, located in the multilayer siliciclastic basin in the Madrid region, in the center of the Iberian Peninsula. Given the small lateral continuity that the layers considered in isolation show in this type of multilayer aquifer, geophysical stretches, with their corresponding average lithological assignments, have been established to achieve this objective from the well logs. These stretches allow for mapping the internal lithology in the studied area, obtaining a correlation of greater geological scope than that provided by the correlation between layers. Subsequently, the possible correlation of the lithological stretches selected in each of the boreholes was analyzed, verifying their lateral continuity and establishing an NNW-SSE section in the study area. In this work, the transcendence of the correlation of wells up to great distances (about 8 km in total, and average distance of 1.5 km between wells) is focused on the fact that, if there is a presence of pollutant in certain aquifer stretches in a part of the studied area, overexploitation in the Madrid basin will cause the mobilization of this pollutant to the whole basin, with a possible impact on non-polluted areas.

Assessing heterogeneous groundwater systems: Geostatistical interpretation of well logging data for estimating essential hydrogeological parameters

“…This spatial heterogeneity complicates the ability to accurately estimate parameters such as hydraulic conductivity and the contaminants distribution 3 – 6 . Traditional geological and hydrogeological methods can provide valuable insights, but they often fall short of capturing the full lithological variability within the aquifers 7 – 9 . On the other hand, Geophysical well logging offers a unique opportunity to attain a more comprehensive understanding of the aquifer system as it gives a continuous estimation of the aquifer characteristics 10 – 13 .…”